mem: Add checks to sendTimingReq in cache
mem: Add checks to sendTimingReq in cache

A small fix to ensure the return value is not ignored.

hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5,hoangt/tpzsimul.gem5